Electromagnet



July 4, 1939. D. ELLIS E1 m.

BLECTROIAGHET FilOd July 31, 1936 INVENTORS. Delber/ 57/115 and afrmy.

WITN ESSES:

Patented July 4, 1939 UNITED STATES PATENT OFFICE ELECTROMAGNETApplication July 31, 1936, Serial No. 93,590

9 Claims.

This invention relates to electromagnets.

In the construction of contactors, the movable contact members aresometimes carried by a bar which may be actuated to carry them intoengagement with complementary contact members to what is generallydescribed as a circuit closing position. The bar is usually somechanically connected to the armature of an electromagnet that when apredetermined voltage is impressed on the actuating coil of theelectromagnet the armature and bar are actuated to move the contactmembers into closed position.

In practice, however, it is found that the armature and the bar carryingthe movable contact members are not always actuated to a circuit closingposition when the desired pick-up voltage is imposed on the actuatingcoil of the electromagnet. This is especially true in applications ofcontactors of this type on board ship where the motion of the ship tiltsthe electromagnet and the contactors forward and backward with respectto a vertical position.

When the contactor and the electromagnet for actuating the contactmembers are tipped in the forward position, the center mass of thearmature actuated by the electromagnet is so shifted that apredetermined pick-up Voltage impressed on the electromagnet coil willnot cause sufficient magnetic pull to actuate the armature and the barcarrying the contact members to a circuit closing position. When thecontactor is tilted backward from a vertical position, the center ofmass of the armature is so shifted that the armature of theelectromagnet and the bar may be moved to the circuit closing positionwhen .2. voltage less than the predetermined pick-up voltage isimpressed on the actuating coil.

In this type of apparatus, the electromagnet is often subjected tophysical shocks which, if

the armature is in a circuit closing position, will cause the armatureto be jarred out of its circuit closing position. If the armature is inits circuit interrupting position and the electromagnet is subjected toa shock, the resultant forces of the shock sometimes cause the armatureto be actuated to a circuit closing position. This movement of thearmature and the bar carried thereby often results in serious damage toapparatus connected in circuit by the contactors.

An object of this invention is to provide for the actuation of thearmature of an electromagnet to complete a magnetic circuit upon theoccurrence of a predetermined magnetic pull when the electromagnet is ina vertical position or tilted 65. at an angle to the vertical position.

Another object of this invention is to provide for stabilizing thearmature of an electromagnet to prevent movement of the armature whenthe electromagnet is subjected to shocks.

Another object of this invention is the provision 5 of a shock absorberfor electromagnets.

Other objects of this invention will be apparent from the followingdescription when taken in conjunction with the accompanying drawing, in

which:

Figure 1 is a front elevational view of an electromagnet embodying thefeatures of this invention,

Fig. 2 is a side elevational view of the electromagnet shown in Fig. 1,15

Fig. 3 is a view in section taken. along lines III-III of Fig. 1 andillustrating the shock absorber as embodied in this invention, and

Figs. 4 and 5 are schematic views of the electromagnet with its armaturein the circuit inter- 20 rupting position in forward and backward tiltedpositions, respectively, from a vertical position.

Referrng to the drawing and Figs. 1 and 2 in particular, this inventionis illustrated with reference to an electromagnet lb comprising a yoke25 member l2, an actuating coil l4 suitably disposed on the yoke memberand an armature l6 disposed for movement to complete a magnetic circuitwith the yoke member 12. In order to limit the movement of the armatureto the open position 30 of the electromagnet, a stop bracket 18 having aflange 2G projecting into the path of movement of the armature [6 may becarried by the panelboard 22 upon which the electromagnet ll] ismounted. The electromagnet it may be secured to the panelboard 22 insome suitable manner, such as by bolts 24.

In order to provide for supporting the armature l6 and for carrying itinto and out of the closed position in which it completes a magneticcircuit with the yoke member l2, the armature i6 is suitably carried byan armature arm 26 as by means of the pin 28. The armature arm 26comprises the plates 30 between which the armature i6 is carried,disposed on a bar 32 which 45' bracket38 for carryingthearmaturearm. The65' The members of bracket 38 may be suitably mounted on the panelboard22 as by means of the bolts 46. The pivot pin projects through suitableopenings in the legs of the tail piece 34 and carries the armature arm26.

The bar 32 extends from the armature arm and carries the movable contactmembers (not shown) of the contactor, the operation of which it isdesired to control by means of the electromagnet H]. In order to providea suitable support for the end of the pin 42 opposite the bracket 38, aplate 44 is disposed on the bar 32, for carrying the other end of thepin 42. A support similar to bracket 38 may be provided on thepanelboard 22 at the other end of the bar 32 which carries the movablecontact members of the contactor between its ends for providing asuitable bearing pivot point for the other end of the bar which carriesanother plate similar to plate 44 disposed to receive another pivot pinsimilar to the pin 42.

In order to provide for the actuation of the armature Hi to a closedposition only upon the occurrence of a predetermined magnetic pull inthe yoke member [2 and to stabilize the armature against shocks whichmight occur at any time, a weight member 46 is carried by the pivot pin42 between the legs of the tail piece 34 for cooperating with thearmature arm, as will be explained hereinafter. Since the said member isdisposed between the legs of the tail piece and is pivotally carried bythe pin 42, any movement of the said member is definitely fixed withrespect to the armature and armature arm as sembly and is within theirplane of movement. The weight member 46 as employed in this inventioncomprises a substantially U-shaped link 48 having an Opening at one endthereof for receiving the pivot pin 42. A weight 58 is mechanicallyconnected to the other end of the link, as by means of the bolt 52.Since the armature l6, the armature arm 26 and the weight member 46 arelinked together by pins 28 and 42, the assembly may be termed anarticulated armature having an upper portion comprising the armature andarmature arm and a lower portion comprising the weight member.

In the particular embodiment shown in the drawing, projections 56 and 58are provided near the end of the U-shaped link 48 adjacent the pivot pin42 for cooperating with the pin 35 carried by the tail piece 34 tostabilize the armature 16 against shocks. As shown, the projections 56and 58, respectively, extend from the link to a position above and belowthe pin 35 where they are adapted to engage the pin 35 and cooperatetherewith to control the movement of the armature arm 26.

In operation, if the actuating coil I4 is energized toprovide apredetermined magnetic pull, the armature I8 is actuated to complete amagnetic circuit with the yoke member 12. When the armature i6 is in theclosed circuit position, the weight member 46 stands in the positionshown in Fig. 2 of the drawing. In this position, it is noted that thereis a. clearance between the pin 35 carried by the armature arm 26 andthe projections 56 and 58 of the weight member 46.

If the electromagnet I6 is subjected to a shock when in the closedvertical position, the armature I6 is retained in the closed position bythe weight member 46, since the shock is transmitted through thearmature l6, armature arm 26 and pin 35 to the weight member 46 to causea bobbing movement of the weight member about its pivot pin 42. Thebobbing movement of the weight member is occasioned by the clearancebetween the pin 35 and the projections 56 and 58 of the weight member.The clearance provides a lost motion between the weight member and theprojections sothat as the weight member moves about the pivot pin 42 inresponse to the force of the shock, the projections 56 and 58alternately strike the pin 35 until the force of the shock is dissipatedby movement of the weight 50.

If the actuating coil is deenergized, the armature drops to a circuitinterrupting position, and the tail piece 34 of the armature arm movesin a counterclockwise direction about the pivot pin 42 to a positionwhere the projection 56 engages the pin 35. Thus the weight member 46tends to bias the armature to its circuit closing position, so that byadjusting the weight 58 of the weight member 46 the pick-up voltage atwhich the armature I6 is actuated to its circuit closing position mayeasily be determined.

If the electromagnet is tilted forward with respect to its verticalposition when the armature is in its circuit interrupting position, asshown in Fig, 4, the weight member 46 is moved in a counter-clockwisedirection about its pivot pin 42 to shift the center of mass of thearmature. As the weight member 46 moves about its pivot pin 42 inresponse to a tilting of the electromagnet, the center of mass of theweight member shifts and the weight member tends to bias the armature toa circuit closing position. The shifting of the center of mass of theweight member so equalizes the shifting of the center of mass of thearmature that the armature will be actuated to its circuit closingposition when the actuating coil is energized to provide thepredetermined magnetic pull.

If the electromagnet is tilted backwards with respect to a verticalposition when the armature is in its circuit interrupting position, asshown in Fig. 5, the pin 35 carried by the tail piece of the armaturearm engages the lower projection 58 of the weight member 46 to rotatethe weight member in a clockwise direction about the pivot pin 42. Inthis tilted position, the weight member 46 acting through the pin 35tends to so bias the armature I6 carried by the armature arm 26 to itscircuit interrupting position, that it will not move to complete themagnetic circuit with the yoke member until after the actuating coil 14is energized to provide the predetermined magnetic pull.

If the electromagnet is subjected to a shock when tilted backwards withits armature in the circuit interrupting position, the armature will notdrop to its circuit closing position but instead the shocks will betransmitted from the armature through the armature arm to the weightmember 46 to cause a bobbing action of the weight member to dissipatethe force of the shock. The armature is not actuated to its closedposition during the bobbing of the weight member 46 because as theweight member bobs it strikes the lower side of the pin 35 carried bythe armature arm and thus tends to bias the armature to its openposition.

Thus as the electromagnet is tilted forward or backward with respect toa vertical position, the force of any shocks applied to theelectromagnet will be dissipated by the bobbing action of the weightmember.

By providing the controlling electromagnet of a contactor with theweight member, as herein disclosed, it is evident that the weight of theweight member may be so selected that the armature of the electromagnetwill not be moved to its circuit closing position to actuate the contactmembers of the contactor unless the actuating coil of the electromagnetis energized to provide a predetermined magnetic pull. The shift of thecenter of mass of the weight member in the different positions of theelectromagnet is sufiicient to require a predetermined magnetic pull inthe yoke member before the armature is actuated to its circuit closingposition. Further by means of this invention even though theelectromagnet is tilted to an angle with respect to a vertical position,the armature is stabilized against any movement occasioned by shocks.

Although this invention has been described with reference to aparticular embodiment thereof, it is, of course, not to be limitedthereto except insofar as is necessitated by the prior art and the scopeof the appended claims.

We claim as our invention:

1. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an armature for completing a magneticcircuit with the yoke member, a pivotally mounted armature arm forcarrying the armature, the armature arm disposed for movement from anopen position to carry the armature to a closed position to complete themagnetic circuit when the coil is energized to provide a predeterminedmagnetic pull in the yoke member, a pin carried by the armature arm, aweight member carried by the armature arm, a plurality of means disposedon the weight member for engaging the pin when the armature arm is inthe open position and the electromagnet is at an angle to a verticalposition, one of the plurality of means disposed to engage the pin to sobias the armature to the closed position when the electromagnet istipped forward at an angle to a vertical position that the armature isactuated to complete the magnetic circuit when the coil is energized toprovide the predetermined magnetic pull in the yoke member, another ofthe plurality of means disposed to engage the pin to so bias thearmature arm to the open position when the electromagnet is tippedbackward at an angle to a vertical position to prevent the actuation ofthe armature to complete the magnetic circuit until the coil isenergized to provide the predetermined magnetic pull in the yoke member,the'weight member also providing a mass for cooperating with thearmature arm to stabilize the armature against movement when subjectedto shocks.

2. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an armature for completing a magneticcircuit with the yoke member, an armature arm for carrying the armature,a pin disposed for pivotally supporting the armature arm, the armaturearm being disposed for movement from an open position to carry thearmature to a closed position to complete the magnetic circuit when thecoil is r energized to provide a predetermined magnetic pull in the yokemember, a pin carried by the armature arm, and means movably supportedon the armature arm supporting pin for limited pivotal movement relativeto the armature arm and independent thereof and in a fixed plane withrespect to the armature and armature arm for all positions of theelectromagnet for cooperating with the pin carried by the armature armwhen the armature arm is in an open position and the electromagnet is atan angle to a vertical position to permit the armature to be actuated tothe closed position when the coil is energized to provide thepredetermined magnetic pull, the means also providing a mass forcooperating with the armature arm to stabilize the armature againstshocks.

3. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an armature for completing a magneticcircuit with the yoke member, an armature arm for carrying the armature,a pin disposed for pivotally supporting the armature arm, the armaturearm being disposed for movement from an open position to carry thearmature to a closed position to complete the magnetic circuit when thecoil is energized to provide a predetermined magnetic pull in the yokemember, a pin carried by the armature arm, a weight member pivotallycarried by the supporting pin for limited pivotal movement relative tothe armature arm and independent thereof and having a plane of movementsubstantially parallel to the plane of movement of the armature for allpositions of the electromagnet, and means disposed on the weight memberfor engaging the pin carried by the armature arm when the armature is inthe open position and the electromagnet is at an angle to' a verticalposition whereby the weight member cooperates with the armature arm topermit the armature to be actuated to the closedposition when the coilis energized to provide the predetermined pull, the weight member alsoproviding a mass for cooperating with the armature arm to stabilize thearmature against shocks.

4. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an armature assembly for completing amagnetic circuit with the yoke member, a pin disposed for pivotallysupporting the armature assembly, a pin carried by the armatureassembly, and a member carried by the supporting pin of the armatureassembly and disposed thereon for limited independent pivotal movementrelative to the armature assembly and for movement in a fixed plane withrespect to the armature for all positions of the electromagnet tocooperate with the pin carried by the armature assembly to compensatefor the tilting of the electromagnet from the vertical to provide forthe operation of the armature by a substantially constant magnetic pullindependently of the position in which the electromagnet stands, themember also cooperating with the pin carried by the armature assembly tostabilize the armature against movement when subjected to shocks.

5. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an articulated armature assembly forcompleting a magnetic circuit with the yoke member, the articulatedarmature assembly having an upper and a lower portion, a pin disposedfor pivotally supporting the upper and lower portions in assembledrelation, a pin carried by the upper portion of the armature assembly,the upper portion being disposed for predetermined angular movementindependently of the lower portion when the electromagnet stands in avertical closed position, the lower portion being disposed for movementin a fixed plane with respect to the upper portion of the assembly forall positions of the electromagnet, means carried by the lower portionfor engaging with the pin carried by the upper portion to cooperatetherewith to compensate for the tilting of the electromagnet from thevertical to provide for the operation of the armature by a substantiallyconstant magnetic pull independently of the position in which theelectromagnet stands.

6. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an articulated armature assembly forcompleting a magnetic circuit with the yoke member, the articulatedarmature assembly having an upper and a lower portion, a pin disposedfor pivotally supporting the upper and lower portions in assembledrelation, a pin carried by the upper portion of the armature assembly,the upper por tion being disposed for predetermined angular movementindependently of the lower portion when the electromagnet stands in avertical closed position, the lower portion being disposed for movementin a fixed plane with respect to the upper portion of the assembly forall positions of the electromagnet, a plurality of means carried by thelower portion for engaging with the pin carried by the upper portion ina predetermined manner to cooperate therewith to compensate for thetilting of the electromagnet from the vertical to provide for theoperation of the armature by a substantially constant magnetic pull, theplurality of means carried by the lower portion being disposed toalternately engage the pin carried by the upper portion to cooperatetherewith to stabilize the upper portion against movement when theelectromagnet is subjected to shocks.

7. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an articulated armature assembly forcompleting a magnetic circuit with the yoke member, the articulatedarmature assembly having an upper and a lower portion, a pin disposedfor pivotally supporting the upper and lower portions in assembledrelation, the upper portion of the assembly including an armature,armature arm and a pin carried by the armature arm and being disposedfor predetermined angular movement, the lower portion of the assemblycomprising a weight member and a plurality of means carried thereon forengaging the pin carried by the armature arm when the electromagnet istipped forward or backward at an angle to a vertical position, theweight member cooperating with the upper portion of the assembly whenany one of said plurality of means engages the pin carried by thearmature arm to control and permit movement of the armature only inresponse to or failure of a predetermined energization of the coil andyoke member, the weight member also providing a mass for cooperatingwith the upper portion of the assembly to stabilize the armature againstshocks.

8. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an articulated armature assembly forcompleting a magnetic circuit with the yoke member, the articulatedarmature assembly having an upper and a lower portion, a pin disposedfor pivotally supporting the upper and lower portions in assembledrelation, the upper portion of. the assembly including an armature, anarmature arm and a pin carried thereon and being disposed forpredetermined angular movement, the lower portion of the assemblycomprising a weight member and a plurality of means carried thereon forengaging the pin carried by the armature arm when the upper portion ofthe assembly is in the open position and the electromagnet is at anangle to a vertical position, one of the plurality of means disposed toengage the pin to so bias the upper portion of the assembly toward theclosed position when the electromagnet is tipped forward at an angle toa vertical position that movement of the armature to the closed positionis permitted when the coil is energized to provide a predeterminedmagnetic pull in the yoke member, another of the plurality of meansdisposed to engage the pin to so bias the upper portion of the assemblytoward the open position when the electromagnet is tipped backward at anangle to a vertical position to prevent the actuation of the upperportion to the closed position until the coil is energized to providethe predetermined magnetic pull in the yoke member, the weight memberalso providing a mass for cooperating with the upper portion of theassembly to stabilize the armature against shocks.

9. In an electromagnet, in combination, a yoke member, a coil forenergizing the yoke member, an articulated armature assembly forcompleting a magnetic circuit with the yoke member, the articulatedarmature assembly having an upper and a lower portion, a pin disposedfor pivotally supporting the upper and lower portions in assembledrelation, the upper portion of the assembly comprising an armature, anarmature arm for carrying the armature, the armature arm terminating ina tail piece having a plurality of legs, and a pin carried between thelegs of the tail piece, the lower portion of the assembly comprising aweight member disposed to be carried on the supporting pin between thelegs of the tail piece and having a plane of movement fixed with respectto the plane of movement of the upper portion of the assembly, meanscarried by the weight member for engaging the pin carried by the legs ofthe tail piece when the electromagnet is tipped forward or backward atan angle to a vertical position, the weight member cooperating with theupper portion of the assembly when said means engages the pin to controland permit movement of the armature only in response to or failure of apredetermined energization of the coil and yoke member, the weightmember also providing a mass for cooperating with the upper portion ofthe assembly to stabilize the armature against shocks.

DELBERT ELLIS. GEORGE C. ARMSTRONG.

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